The relationship between interpregnancy interval (IPI) and mother’s preceding pregnancies (PP)

Abstract Introduction Following the investigation of the mother’s preceding pregnancies on fetal development and postnatal survival of the neonate, we turned our attention to an earlier period, that is the interval separating the onset of the current pregnancy from the end of the preceding one. The objectives of this study is to investigate the variations of interpregnancy interval length associated to the mother’s preceding pregnancies. Methods A population of 7773 neonates, alive at the time of hospital discharge, were divided into cohorts according to the current neonate’s sex and number and sex of the mother’s preceding pregnancies. Interpregnancy interval average of each cohort of same neonate’s sex and mother’s parity, but different configuration of preceding pregnancies, were measured and compared. Results A positive association was found between mother’s preceding pregnancies and length of interpregnancy interval when current pregnancy and preceding pregnancy were of the same sex, and a negative association when they were of opposite sex. Discussion Interpregnancy interval length follows a pattern regarding the gravida’s preceding pregnancy similar to the other early life indicators pattern, birth weight, placenta weight, gestation length and neonatal survival. Our results confirm and complete an immunological explanation of the indicators variations associated to the gravida’s preceding pregnancy.